"We try to react quickly to remove reported language or images that violate our terms and we try to make it very easy for people to report questionable content using links located throughout the site."

They claim that Facebook has refused to remove some images, reasoning that while some users may find them offensive they are not in violation of its policies.

One image highlighted on the website WomenActionMedia (WAM) shows a woman lying in a pool of blood with the slogan "I like her for her brains".

One Facebook group noted by WAM is titled "Slapping Hookers in the face with a shoe". It currently has 35 likes, according to WAM.

Many of the images highlighted so far have now been deleted, but a coalition of groups including the UK-based Everyday Sexism Project, WAM and around 40 other groups called on the social network to go further and revise its policies.

A Change.org petition has gathered more than 220,000 signatures demanding that Facebook remove the highlighted images, and revise its policies to treat images which promote rape or violence against women in a similar way to those deemed racist.

The BBC reports that more than 50,000 people have tweeted in support of the campaign, and 5,000 people have emailed advertisers calling for a boycott.

1. Make a public statement that rape is never acceptable; that promoting sexual violence and violence against women is repugnant; that Facebook will remove content that advocates rape, sexual violence, and violence against women; and that the terms of service/community standards will be updated to specify this.

2. Address in a public statement that the previous "pub joke" defense was poorly stated, explaining that alleging humour does not give a free pass to promote any hate content; that Facebook does not consider promoting violence against women or sexual assault to be a joke or funny; and that such content will be held to the same standard as any violence against any other group or individual.

3. Be transparent about the content monitoring process; to state publicly if and how many pages are removed that promote sexual violence or violence against women; and to establish relationships with experts in sexual violence and violence against women who will help identify content that needs to be removed.

4. Update its terms of service/community standards to specify that: "Content earnestly promoting violence against women or sexual violence violates Facebook's terms of use and will accordingly be removed whenever reported." In addition to the internal reporting system, provide a public contact email for users to register complaints about content that violates the terms of service/community standards, that will acknowledge receipt and respond with a decision on whether or not to remove.